package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.CACHE_SHOP_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;
    @Override
    public Result queryById(String id) {
        // 解决缓存穿透
       // Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY + id,
        //        id, Shop.class,this::getById, 30L, TimeUnit.MINUTES);

       // Shop shop = queryWithMutex(id);
       // Shop shop = queryWithLogicalExpire(id);
        //缓存击穿
        Shop shop = cacheClient
                .queryWithPassThrough(CACHE_SHOP_KEY ,id,Shop.class,this::getById,20L, TimeUnit.SECONDS);
        if (shop == null) {
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }


    public static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);


    public Shop queryWithLogicalExpire(String id) {
        //从redis查
        String shopJson = stringRedisTemplate.opsForValue().get("cache:shop:" + id);
        if (StrUtil.isBlank(shopJson)) {
            return null;
        }

        // 判断是否过期
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        JSONObject data = (JSONObject)redisData.getData();
        Shop shop = JSONUtil.toBean(data, Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        if(expireTime.isAfter(LocalDateTime.now())){
            return shop;
        }

        String lockKey = "lock:shop:" + id;
        boolean isLock = tryLock(lockKey);
        if(isLock) {
            try {
                // 获取锁成功，开启独立线程，实现缓存重建
                CACHE_REBUILD_EXECUTOR.submit(() -> {
                    try {
                        // 重建缓存
                        this.saveShop2Redis(id, 20L);
                    } catch (Exception e) {
                        throw new RuntimeException(e);
                    } finally {
                        // 释放锁
                        unLock(lockKey);
                    }
                });
            } finally {
                unLock(lockKey);
            }


        }
        return shop;
    }
    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }
    private void unLock(String key){
        stringRedisTemplate.delete(key);
    }


    public Shop queryWithMutex(String id) {
        //从redis查
        String shopJson = stringRedisTemplate.opsForValue().get("cache:shop:" + id);
        if (StrUtil.isNotBlank(shopJson)) {
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        if (shopJson != null) {
            return null;
        }
        Shop shop = null;
        try {
            boolean isLock = tryLock("lock:shop:" + id);
            if (!isLock) {
                // 获取锁失败，休眠并重试
                    Thread.sleep(50);
                    return queryWithMutex(id);
            }

            // 从数据库查
           shop = getById(id);
            if (shop == null) {
                //空值写入redis
                stringRedisTemplate.opsForValue().set( "cache:shop:" + id, " ",2L , TimeUnit.MINUTES);
                return null;
            }

            //缓存到redis
            stringRedisTemplate.opsForValue().set("cache:shop:" + id,
                    JSONUtil.toJsonStr(shop),
                    30L, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            unLock("lock:shop:" + id);
        }

        return shop;
    }
    public Shop queryWithPassThrough(String id) {
        //从redis查
        String shopJson = stringRedisTemplate.opsForValue().get("cache:shop:" + id);
        if (StrUtil.isNotBlank(shopJson)) {
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        if (shopJson != null) {
            return null;
        }
        // 从数据库查
        Shop shop = getById(id);
        if (shop == null) {
            //空值写入redis
            stringRedisTemplate.opsForValue().set( "cache:shop:" + id, " ",2L , TimeUnit.MINUTES);
            return null;
        }

        //缓存到redis
        stringRedisTemplate.opsForValue().set("cache:shop:" + id,
                JSONUtil.toJsonStr(shop),
                30L, TimeUnit.MINUTES);
        return shop;
    }




    public void saveShop2Redis(String id, Long expireSeconds ) {
        //1.查询店铺数据
        Shop shop = getById(id);
        //2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3.写入redis
        stringRedisTemplate.opsForValue().set("cache:shop:" + id, JSONUtil.toJsonStr(redisData));
    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        if (shop.getId() == null) {
            return Result.fail("店铺id不能为空");
        }
        // 写入数据库
         updateById(shop);
        // 缓存重建
        stringRedisTemplate.delete("cache:shop:" + shop.getId());

        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要坐标查
        if (x == null || y == null) {
            // 根据类型分页查询
            Page<Shop> page =query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        //3.查询redis，按照距离排序，分页
        String key = "shop:geo:byType:" + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key, GeoReference.fromCoordinate(x, y)
                        , new Distance(5000)
                        , RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeCoordinates().limit(end));
        //4.根据依赖查询
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip( from).forEach(result ->
        {
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));

            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        List<Shop> shops = query()
                .in("id", ids)
                .last("ORDER BY FIELD(id," + StrUtil.join(",", ids) + ")").list();
        for ( Shop shop : shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shops);
    }
}
